1. Field of the Invention
The embodiments of the invention generally relate to intra-process monitoring and control and, more particularly, to embodiments of a passive resonator capable of being wirelessly interrogated during processing by a processing tool, a system incorporating the passive resonator for real-time intra-process monitoring and control, and an associated method.
2. Description of the Related Art
As lithographic geometries are reduced for each successive semiconductor process generation, the effects of process variability have become significant first order issues. Designers are faced with creating tradeoffs between timing margin, power, and performance. Tighter process controls enable lower power, higher performance, and/or higher yielding products. However, the ability to control processes to tighter tolerances is limited by difficulties encountered in obtaining actual in-line (i.e., intra-process) measurements for a given wafer or for a given site on a given wafer.
For example, during rapid thermal anneal (RTA) processes, temperature variations can occur between RTA chambers and within a single chamber from wafer to wafer and at different locations on a single wafer. Such temperature variations can result in variations in dopant activation, dopant diffusion rates, etc., and can thereby result in performance variations from chip to chip and/or from device to device on a single chip. Unfortunately, local on-wafer temperature measurements can not generally be obtained during RTA processing. Thus, current RTA process control techniques involve iterative process and measurement sequences that are used to achieve average process conditions between and within RTA chambers. However, such techniques are costly in terms of time and yield. Therefore, there is a need in the art for an on-wafer (e.g., either on-chip or within the scribe-line) structure that allows for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby allows for real-time process control.